The code paths to interact with zlib has been cleaned up in
preparation for building with zlib-ng.
* ps/zlib-ng:
ci: make "linux-musl" job use zlib-ng
ci: switch linux-musl to use Meson
compat/zlib: allow use of zlib-ng as backend
git-zlib: cast away potential constness of `next_in` pointer
compat/zlib: provide stubs for `deflateSetHeader()`
compat/zlib: provide `deflateBound()` shim centrally
git-compat-util: move include of "compat/zlib.h" into "git-zlib.h"
compat: introduce new "zlib.h" header
git-compat-util: drop `z_const` define
compat: drop `uncompress2()` compatibility shim
More build fixes and enhancements on meson based build procedure.
* ps/build-meson-fixes:
ci: wire up Visual Studio build with Meson
ci: raise error when Meson generates warnings
meson: fix compilation with Visual Studio
meson: make the CSPRNG backend configurable
meson: wire up fuzzers
meson: wire up generation of distribution archive
meson: wire up development environments
meson: fix dependencies for generated headers
meson: populate project version via GIT-VERSION-GEN
GIT-VERSION-GEN: allow running without input and output files
GIT-VERSION-GEN: simplify computing the dirty marker
Following the procedure we established to introduce breaking
changes for Git 3.0, allow an early opt-in for removing support of
$GIT_DIR/branches/ and $GIT_DIR/remotes/ directories to configure
remotes.
* ps/3.0-remote-deprecation:
remote: announce removal of "branches/" and "remotes/"
builtin/pack-redundant: remove subcommand with breaking changes
ci: repurpose "linux-gcc" job for deprecations
ci: merge linux-gcc-default into linux-gcc
Makefile: wire up build option for deprecated features
Switch over the "linux-musl" job to use Meson instead of Makefiles. This
is done due to multiple reasons:
- It simplifies our CI infrastructure a bit as we don't have to
manually specify a couple of build options anymore.
- It verifies that Meson detects and sets those build options
automatically.
- It makes it easier for us to wire up a new CI job using zlib-ng as
backend.
One platform compatibility that Meson cannot easily detect automatically
is the `GIT_TEST_UTF8_LOCALE` variable used in tests. Wire up a build
option for it, which we set via a new "MESONFLAGS" environment variable.
Note that we also drop the CC variable, which is set to "gcc". We
already default to GCC when CC is unset in "ci/lib.sh", so this is not
needed.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The zlib-ng library is a hard fork of the old and venerable zlib
library. It describes itself as zlib replacement with optimizations for
"next generation" systems. As such, it contains several implementations
of central algorithms using for example SSE2, AVX2 and other vectorized
CPU intrinsics that supposedly speed up in- and deflating data.
And indeed, compiling Git against zlib-ng leads to a significant speedup
when reading objects. The following benchmark uses git-cat-file(1) with
`--batch --batch-all-objects` in the Git repository:
Benchmark 1: zlib
Time (mean ± σ): 52.085 s ± 0.141 s [User: 51.500 s, System: 0.456 s]
Range (min … max): 52.004 s … 52.335 s 5 runs
Benchmark 2: zlib-ng
Time (mean ± σ): 40.324 s ± 0.134 s [User: 39.731 s, System: 0.490 s]
Range (min … max): 40.135 s … 40.484 s 5 runs
Summary
zlib-ng ran
1.29 ± 0.01 times faster than zlib
So we're looking at a ~25% speedup compared to zlib. This is of course
an extreme example, as it makes us read through all objects in the
repository. But regardless, it should be possible to see some sort of
speedup in most commands that end up accessing the object database.
The zlib-ng library provides a compatibility layer that makes it a
proper drop-in replacement for zlib: nothing needs to change in the
build system to support it. Unfortunately though, this mode isn't easy
to use on most systems because distributions do not allow you to install
zlib-ng in that way, as that would mean that the zlib library would be
globally replaced. Instead, many distributions provide a package that
installs zlib-ng without the compatibility layer. This version does
provide effectively the same APIs like zlib does, but all of the symbols
are prefixed with `zng_` to avoid symbol collisions.
Implement a new build option that allows us to link against zlib-ng
directly. If set, we redefine zlib symbols so that we use the `zng_`
prefixed versions thereof provided by that library. Like this, it
becomes possible to install both zlib and zlib-ng (without the compat
layer) and then pick whichever library one wants to link against for
Git.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The meson-driven build is now aware of "git-subtree" housed in
contrib/subtree hierarchy.
* ps/build-meson-subtree:
meson: wire up the git-subtree(1) command
meson: introduce build option for contrib
contrib/subtree: fix building docs
The CSPRNG backend is not configurable in Meson and isn't quite
discoverable, either. Make it configurable and add the actual backend
used to the summary.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Meson does not yet know to build our fuzzers. Introduce a new build
option "fuzzers" and wire up the fuzzers in case it is enabled. Adapt
our CI jobs so that they build the fuzzers by default.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
With 57ec9254eb (docs: introduce document to announce breaking changes,
2024-06-14), we have introduced a new document that tracks upcoming
breaking changes in the Git project. In 2454970930 (BreakingChanges:
early adopter option, 2024-10-11) we have amended the document a bit to
mention that any introduced breaking changes must be accompanied by
logic that allows us to enable the breaking change at compile-time.
While we already have two breaking changes lined up, neither of them has
such a switch because they predate those instructions.
Introduce the proposed `WITH_BREAKING_CHANGES` preprocessor macro and
wire it up with both our Makefiles and Meson. This does not yet wire up
the build flag for existing deprecations.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
We unconditionally wire up building command completion present in the
"contrib/" directory. This may or may not be what users want, and we
don't provide a way to disable it.
Introduce a new "contrib" build option. This option is introduced as an
array so that users can manually pick which exact features they want to
include from the "contrib" directory. By default, we build and install
shell completions, which is a commonly used feature and also the current
default.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
meson-based build now supports the unsafe-sha1 build knob.
* ps/meson-weak-sha1-build:
meson: provide a summary of configured backends
meson: wire up unsafe SHA1 backend
meson: add missing dots for build options
meson: simplify conditions for HTTPS and SHA1 dependencies
meson: require SecurityFramework when it's used as SHA1 backend
meson: deduplicate access to SHA1/SHA256 backend options
meson: consistenlty spell 'CommonCrypto'
* ps/meson-weak-sha1-build:
meson: provide a summary of configured backends
meson: wire up unsafe SHA1 backend
meson: add missing dots for build options
meson: simplify conditions for HTTPS and SHA1 dependencies
meson: require SecurityFramework when it's used as SHA1 backend
meson: deduplicate access to SHA1/SHA256 backend options
meson: consistenlty spell 'CommonCrypto'
In 06c92dafb8 (Makefile: allow specifying a SHA-1 for non-cryptographic
uses, 2024-09-26), we have introduced a cryptographically-insecure
backend for SHA1 that can optionally be used in some contexts where the
processed data is not security relevant. This effort was in-flight with
the effort to introduce Meson, so we don't have an equivalent here.
Wire up a new build option that lets users pick an unsafe SHA1 backend.
Note that for simplicity's sake we have to drop the error condition
around an unhandled SHA1 backend. This should be fine though given that
Meson verifies the value for combo-options for us.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Most of our Meson build options end with a trailing dot, but those for
our SHA1 and SHA256 backends don't. Add it.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The 'CommonCrypto' backend can be specified as HTTPS and SHA1 backends,
but the value that one needs to use is inconsistent across those two
build options. Unify it to 'CommonCrypto'.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
While our Makefile supports both Asciidoc and AsciiDoctor, our Meson
build instructions only support the former. Wire up support for the
latter, as well.
Our Makefile always favors Asciidoc, but Meson will automatically figure
out which of both to use based on whether they are installed or not. To
keep compatibility with our Makefile it favors Asciidoc over Asciidoctor
in case both are available.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
A topic to optionally build with meson, which has graduated to
'master' recently, has regressed the normal Makefile build, which
is being corrected.
* ps/build-hotfix:
meson: add options to override build information
GIT-VERSION-GEN: fix overriding GIT_BUILT_FROM_COMMIT and GIT_DATE
GIT-VERSION-GEN: fix overriding GIT_VERSION
Makefile: introduce template for GIT-VERSION-GEN
Makefile: drop unneeded indirection for GIT-VERSION-GEN outputs
Makefile: stop including "GIT-VERSION-FILE" in docs
We inject various different kinds of build information into build
artifacts, like the version string or the commit from which Git was
built. Add options to let users explicitly override this information
with Meson.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
It is possible to configure a Git build without Perl when disabling both
our test suite and all Perl-based features. In Meson, this can be
achieved with `meson setup -Dperl=disabled -Dtests=false`.
It was reported by a user that this breaks the Meson build because
gitweb gets built even if Perl was not discovered in such a build:
$ meson setup .. -Dtests=false -Dperl=disabled
...
../gitweb/meson.build:2:43: ERROR: Unable to get the path of a not-found external program
Fix this issue by introducing a new feature-option that allows the user
to configure whether or not to build Gitweb. The feature is set to
'auto' by default and will be disabled automatically in case Perl was
not found on the system.
Reported-by: Daniel Engberg <daniel.engberg.lists@pyret.net>
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Introduce support for the Meson build system, a "modern" meta build
system that supports many different platforms, including Linux, macOS,
Windows and BSDs. Meson supports different backends, including Ninja,
Xcode and Microsoft Visual Studio. Several common IDEs provide an
integration with it.
The biggest contender compared to Meson is probably CMake as outlined in
our "Documentation/technical/build-systems.txt" file. Based on my own
personal experience from working with both build systems extensively I
strongly favor Meson over CMake. In my opinion, it feels significantly
easier to use with a syntax that feels more like a "real" programming
language. The second big reason is that Meson supports Rust natively,
which may prove to be important given that the project may pick up Rust
as another language eventually.
Using Meson is rather straight-forward. An example:
```
# Meson uses out-of-tree builds. You can set up multiple build
# directories, how you name them is completely up to you.
$ mkdir build
$ cd build
$ meson setup .. -Dprefix=/tmp/git-installation
# Build the project. This also provides several other targets like
e.g. `install` or `test`.
$ ninja
# Meson has been wired up to support execution of our test suites.
# Both our unit tests and our integration tests are supported.
# Running `meson test` without any arguments will execute all tests,
# but the syntax supports globbing to select only some tests.
$ meson test 't-*'
# Execute single test interactively to allow for debugging.
$ meson test 't0000-*' --interactive --test-args=-ix
```
The build instructions have been successfully tested on the following
systems, tests are passing:
- Apple macOS 10.15.
- FreeBSD 14.1.
- NixOS 24.11.
- OpenBSD 7.6.
- Ubuntu 24.04.
- Windows 10 with Cygwin.
- Windows 10 with MinGW64, except for t9700, which is also broken with
our Makefile.
- Windows 10 with Visual Studio 2022 toolchain, using the Native Tools
Command Prompt with `meson setup --vsenv`. Tests pass, except for
t9700.
- Windows 10 with Visual Studio 2022 solution, using the Native Tools
Command Prompt with `meson setup --backend vs2022`. Tests pass,
except for t9700.
- Windows 10 with VS Code, using the Meson plug-in.
It is expected that there will still be rough edges in the current
version. If this patch lands the expectation is that it will coexist
with our other build systems for a while. Like this, distributions can
slowly migrate over to Meson and report any findings they have to us
such that we can continue to iterate. A potential cutoff date for other
build systems may be Git 3.0.
Some notes:
- The installed distribution is structured somewhat differently than
how it used to be the case. All of our binaries are installed into
`$libexec/git-core`, while all binaries part of `$bindir` are now
symbolic links pointing to the former. This rule is consistent in
itself and thus easier to reason about.
- We do not install dashed binaries into `$libexec/git-core` anymore,
so there won't e.g. be a symlink for git-add(1). These are not
required by modern Git and there isn't really much of a use case for
those anymore. By not installing those symlinks we thus start the
deprecation of this layout.
- We're targeting Meson 1.3.0, which has been released relatively
recently November 2023. The only feature we use from that version is
`fs.relative_to()`, which we could replace if necessary. If so, we
could start to target Meson 1.0.0 and newer, released in December
2022.
- The whole build instructions count around 3300 lines, half of which
is listing all of our code and test files. Our Makefiles are around
5000 lines, autoconf adds another 1300 lines. CMake in comparison
has only 1200 linescode, but it avoids listing individual files and
does not wire up auto-configuration as extensively as the Meson
instructions do.
- We bundle a set of subproject wrappers for curl, expat, openssl,
pcre2 and zlib. This allows developers to build Git without these
dependencies preinstalled, and Meson will fetch and build them
automatically. This is especially helpful on Windows.
Helped-by: Eli Schwartz <eschwartz@gentoo.org>
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
